Cleaning deposit devices that form microarrays and the like

ABSTRACT

For depositing fluid dots in an array, e.g., for microscopic analysis, a deposit device, e.g. a pin, cooperating with a fluid source defines a precisely sized drop of fluid of small diameter on a drop carrying surface. Transport mechanism positions the device precisely over the receiving surface and drive mechanism moves the deposit device toward and away from the surface. By repeated action, minute drops of fluid can be deposited precisely in a dense array, preferably under computer control. A mobile-fluid storage device resupplies the deposit device along the array, e.g. in the immediate vicinity of the deposit locations. Mobile annular storage rings are lowered and raised to obtain a supply of fluid, or a mobile multiwell plate is used. Cleaning mechanism is shown, in particular a jet arrangement that directs a jet from a pin or tool axis portal to deeper into the confinement chamber, to scrub along a pin or pin-like structure while inducing an air flow from the working zone to prevent back contamination.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 09/079,324,filed May 14, 1998, entitled “Depositing Fluid Specimens On Substrates,Resulting Ordered Arrays, Techniques For Analysis Of Deposited Arrays”;of U.S. Ser. No. 09/122,216, filed Jul. 24, 1998, now U.S. Pat. No.6,289,846, entitled “Depositing Fluid Specimens On Substrates, ResultingOrdered Arrays, Techniques For Deposition Of Arrays”; and ofInternational PCT/US99/00730, filed Jan. 13, 1999, all of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to devices and systems that deposit smallquantities of fluid upon substrates in a precise manner and in arrays ofdesired density and consistency, and especially to cleaning such systemsand other equipment in the laboratory. The invention is useful, forinstance, in preventing cross-contamination when carrying out reactions,in providing accurate overlays of deposits, and, in particular, inpreparing microscope slides and membranes with biological materials, forinstance, microarrays for drug delivery, gene research and clinical use.

In well developed biological analytical technology, and in recentlydeveloped “Lab on a Chip” or biochip technology, creation of densearrays of fluorescently labeled micro-organisms and DNA assays in a twodimensional field is performed. It is desirable to place the arrays on aconventional microscope slide, or other carrier and to create many suchslides simultaneously in a manufacturing process, while it is importantto avoid contamination in progressing from work with one material toanother.

For biochip technology to proceed to complete fruition, as well as toimprove the application of previous analytical techniques, economicalinstruments and systems have been needed that can, withoutcontamination, rapidly and accurately create the dense array of objectsover a large field portion of a glass microscope slide or a slide-likemember that occupies an area approximately 22 mm wide and 50 mm long ofa slide that is nominally 25 mm×75 mm.

In the deposition upon a microscope slide of discrete, minute quantitiesof a large variety of fluid materials, the volume deposited at adiscrete spot typically may be from a few pico liter to a fraction of amicro liter, depending upon the application. The devices for formingsuch deposits are small and can be hard to clean. The biologicalmaterial carried in this fluid can range from a few strands of shortoligonucleotides in a water solution to a high concentration of longstrands of complex proteins. The properties of these fluids varyenormously. Some are akin to water while others are far more viscous,resembling a light oil or honey. The range of fluids that may beemployed also exhibits wide differences in other properties that makeclean up difficult.

Such a large range of property variations in fluids of interest hascaused difficulties for any single type of process to operate over awide range to produce the desired array of deposits, and to maintainsuch instrument clean and avoid contamination of the procedure.

SUMMARY OF THE INVENTION

One purpose of the invention is to provide a technology adapted to thedeposition of very small drops of fluids, e.g. drops that form spots ofless than about 375 or 300 μm diameter, and in important cases, verymuch smaller than that, and at correspondingly high densities. (As usedin this application, the term fluid “drop” refers to a very smallquantity of fluid, and not to any particular shape of the fluid volume).The fluids and the resultant dots permissibly exhibit a wide range ofproperties such as viscosity, evaporative characteristics, surfacetension, wettability, surfactant characteristic, dynamic contact angleand free surface energy. These and numerous other objectives areachieved by a number of broad features and preferred embodiments whichare individually novel and important and which in many cases cooperatein novel ways to achieve highly effective results.

According to one aspect of the invention, an apparatus for depositingfluid dots on a receiving surface in an array suitable e.g., formicroscopic analysis reaction and the like, is provided, comprising adeposit device and a fluid source which are cooperatively related toenable the deposit device to precisely size a drop of fluid of smalldiameter on a drop-carrying surface of the device, transport mechanismfor positioning the device at a precisely referenced lateral positionover the receiving surface and drive mechanism for moving the depositdevice, relatively, in deposition motion toward and away from thesurface, the apparatus adapted, by repeated action, to deposit the dropsof fluid precisely in a desired array, and then to proceed to a cleaningstation where the instrument is cleaned and then to a resupply stationfor further action with regard to other materials, free ofcontamination, preferably the apparatus being computer controlled.

Preferred embodiments have one or more of the following features.

A cleaning station comprises a fluid jet arranged to blow down along thelength of the deposit device toward its drop-depositing end, the jet anddevice being within a confinement chamber.

The deposit device is a pin or pin-like structure having an end surfacethat carries the fluid drop, preferably the pin or pin-like structurehaving sides that intersect with the end surface to define a sharpperipheral drop-defining rim.

Another broad aspect of the invention is an apparatus for depositingfluid drops on a receiving surface per se, comprising a deposit deviceand a fluid source which are cooperatively related to provide to adrop-carrying surface of the deposit device a precisely sized drop offluid, and a cleaning system that effectively cleans the pin, thedeposit device being a pin or pin-like structure having an end surfacethat serves as the drop-carrying surface, the pin or pin-like structurehaving sides that intersect with the end surface to define a sharpperipheral drop-defining rim.

Preferred pins or pin-like structures have an end surface that isgenerally flat and side surfaces that are cylindrical and smooth.

In many important cases, the fluid source is a mobile fluid storagedevice that is movable relative to an array of deposit locations, thefluid storage device being constructed and arranged to resupply thedeposit device at various locations along the array.

Another broad aspect of the invention is an apparatus for depositingfluid drops on a receiving surface, comprising a deposit device and afluid source which are cooperatively related to provide to the depositdevice a drop of fluid, transport mechanism for positioning the depositdevice over a receiving surface and drive mechanism for moving thedeposit device, relatively, in deposition motion toward and away fromthe receiving surface, the apparatus adapted, by repeated action, todeposit the drops of fluid in a desired array, the fluid source being amobile fluid storage device that is movable relative to the array ofdeposit locations, the fluid storage device being constructed andarranged to resupply the deposit device at various locations along thearray, the system adapted to effectively clean the instruments betweenchanges of fluids.

In preferred embodiments employing a mobile storage device, the depositdevice and the mobile storage device are constructed to supply drops tothe deposit device in the immediate vicinity of the deposit locationsfor respective drops, preferably the mobile fluid storage device and thedeposit device being coupled for transverse motion relative to the arrayand decoupled for movement of the deposit device toward and away fromthe receiving surface.

In many cases the mobile storage devices are preferably constructed andarranged to be replenished from a remotely located large reservoir.

In many cases a mobile storage device holds a volume of fluid having afree surface into which the deposit device is lowered and raised toobtain a fluid drop, preferably the mobile storage device beingconstructed to store a multiplicity of isolated fluid volumes in thewells of a multiwell plate, the apparatus constructed to obtain itsfluid from a selected volume of the plate.

In other important cases a mobile storage device defines a generallyannular fluid retention surface or ring (the term “annular” or “ring”being used to refer broadly to a member that has opposed, or adjacent,surfaces that can hold a mass of fluid between them by surface tensioneffects, accessible to a deposit device), and the deposit device isconstructed to move within the annular retention surface from retractedto extended positions, in the retracted position the drop-carryingsurface of the deposit device being retracted from the surface of fluidretained by the annular surface of the storage device, and in theextended position the drop-carrying surface of the deposit device beingprojected through and beyond the surface of the retained fluid.Advantageously, the cleaning system cleans the pin and ringsimultaneously.

Another broad aspect of the invention is an apparatus for depositingfluid drops on a receiving surface in an array suitable for microscopicanalysis, comprising a deposit device and a fluid source which arecooperatively related to provide to a drop-carrying surface of thedeposit device a precisely sized drop, and a drive mechanism for movingthe deposit device, relatively, in deposition motion toward and awayfrom the receiving surface, the storage device defining a generallyannular fluid retention surface, and the deposit device beingconstructed to move within the annular retention surface from retractedto extended positions, in the retracted position the drop-carryingsurface of the deposit device being retracted from the surface of thefluid retained by the annular surface of the storage device, and in theextended position the drop-carrying surface of the deposit device beingprojected through and beyond the surface of the retained fluid, therelative position of the deposit device and the storage surface beingadjustable so that at the cleaning station an optimal relationship forcleaning can be achieved.

In preferred embodiments, a member that defines an annular fluidretention surface is associated with a driver that moves the memberrelative to the deposit device to a replenishment volume in which themember is immersed to receive a supply of fluid, and to a cleaningposition when the system arrives at the cleaning station.

In certain preferred embodiments the deposit device is a pin or pin-likestructure e.g. having one or more of the features described above, thepin or pin-like structure being mounted within the confines of anannular fluid retention surface and arranged to move axially relativethereto.

The apparatus of any of the aspects and preferred embodiments describedpreferably include a control system adapted to control relative movementof the deposit device to a depositing relationship to the receivingsurface and a cleaning relationship to the cleaning system.

Another broad aspect of the invention is an apparatus for depositing anarray of dots on a receiving surface, comprising a deposit device in theform of a pin or pin-like structure having an end surface capable ofprecisely defining a small drop of fluid, a source of fluid for thedeposit device, mechanism for moving the deposit device relatively overan array of spaced apart deposit locations of a receiving surface,mechanism for repeatedly moving the deposit device, relatively towardand away from the receiving surface to deposit respective drops of fluidat selected deposit locations, a cleaning system, and a control systemadapted to control relative movement of the deposit device between aresupply relationship to the source, a depositing relationship to thesubstrate and a cleaning relationship to the cleaning system.

In embodiments in which the deposit device is associated with a mobilesupply device that travels with it, the deposit device and mobile supplydevice are preferably movable together to the cleaning system inresponse to the control system, preferably the mobile supply devicebeing an annular member through which the deposit device operates.Preferably the cleaning system has a nozzle for directing a flow of airpast the annular structure, preferably a cleaning or drying stationcomprising a circular nozzle is constructed to discharge a conical flowof fluid, preferably compressed air, high pressure liquid, an aerosol orheated air against a deposit device or mobile fluid source, preferablythe deposit device being a pin or pin-like structure surrounded by amobile reservoir in the form of an annular member capable of holding asupply of fluid by surface tension effects, the nozzle flows directed todislodge retained fluid, to clean or to dry the respective parts; insome cases, preferably a circular storage device is associated with aheater, e.g., an induction heater.

Preferably, each device to be cleaned has its own cleaning chamber towhich it travels, for removal of previous fluid, washing and drying in aso-called “one stop shop”.

In certain preferred embodiments of the various aspects and featuresdescribed, there are provided a set of at least two of the depositdevices, preferably many more, at least one fluid source for providing adrop of fluid on each deposit device, and mechanism for moving the pinstogether transversely over an array of spaced apart deposit locations ofthe receiving surface, and to a cleaning station for the respectivedeposit devices, preferably there being at least four of the depositdevices comprising a deposit head. Preferably the apparatus includesmechanism for repeatedly moving each deposit device independently, ormechanism for moving each deposit device simultaneously, relatively,toward and away from the supply device for resupply, the receivingsurface to deposit respective drops at respective deposit locations onthe receiving surface, and, optimally the cleaning station.

For simultaneous actuation, preferably two or more deposit devices aremounted on a common support, driven by a common driver to depositrespective fluid drops on the receiving surface. In cases in which eachdeposit device is associated with a respective storage ring, the storagerings are also mounted on a common support, driven by a common drive;preferably the spacing of the rings corresponds to the spacing of amultiwell storage plate into which the rings are immersed for resupply.In cases in which the deposit device is lowered directly into fluid andraised to obtain its drop, preferably the spacing of the deposit devicescorresponds to the spacing of wells of a predetermined multiwell plate,the multiwell plate being a mobile fluid supply that is constructed toaccompany the deposit device across the substrate. In the case of supplyrings or direct dipping of the deposit devices, preferably the spacingcorresponds to well-to-well spacing of wells of a 96, 384, 864 or 1536well plate, or a spacing of 9 mm or a submultiple of 9 mm. Likewise inthis case and others, the deposit devices register with discretecleaning stations for the individual elements, in which preferably, highspeed fluid flow is directed toward the instruments being cleaned, butin a direction away from the work environment. Preferably, the highspeed flow induces air flow from the work environment along the devicebeing cleaned to create a negative pressure condition in the workenvironment and avoid backflow of contaminants from the containmentchamber.

The apparatus of any of the foregoing is preferably constructed to mounta number of microscope slides or slide-like structures to serve as thereceiving surface, and a control system is constructed and arranged todeposit drops of fluid in selected locations on the slides or slide-likestructures, preferably the fluid source comprising a source ofbiological fluid.

Preferably, for depositing fluid drops in a dense array of mutuallyisolated dots, a deposit assembly is constructed to travel to a cleaningstation, and comprises a fluid source for repeatedly providing adiscrete drop of fluid on the tip of the deposit device, mechanism formoving the device relatively over an array of spaced apart depositlocations of a receiving surface, mechanism for repeatedly moving thedevice, relatively, toward and away from the receiving surfaces todeposit respective dots at respective deposit locations on the surface,preferably the fluid source being a mobile fluid storage device separatefrom the deposit device, which is generally movable over the array ofdeposit locations, the fluid storage device being constructed andarranged to resupply the deposit device at various locations withrespect to the array.

In certain preferred embodiments of this aspect also, the deposit deviceis a slidable pin or pin-like structure constructed and arranged to dipinto a volume of fluid carried by a mobile storage device, preferablythe storage device being constructed to store a multiplicity of isolatedfluid volumes, the apparatus constructed to move the supply devicerelative to the deposit device to select the fluid to be deposited,preferably the storage device being a 96 well plate or a plate having amultiple of 96 wells, and also preferably including at least one drivenstage for moving a selected well of a mobile multiwell plate intoregistry with the deposit device under computer control for enablingmotion of the deposit device to dip into and out of the preselected wellto provide a drop of the selected fluid to the device.

In other preferred embodiments the mobile storage device is an annularring as described above.

Another broad aspect of the invention is a deposit apparatus comprisinga multiplicity of deposit devices as described, mounted for motiontogether in response to a common actuator, preferably the depositdevices comprising deposit pins or pin-like structures adapted to enterrespective cells of a cleaning station of the kind described above.

Another broad aspect of the invention is an apparatus comprising amobile fluid storage device separate from a deposit device and generallymovable over an array of deposit locations, the fluid storage devicebeing constructed and arranged to resupply the deposit device at variouslocations with respect to the array, in one case, preferably the mobilefluid storage device being constructed to store a multiplicity ofisolated fluid volumes, the apparatus constructed to move the mobilestorage device relative to the deposit device to select the fluid to bedeposited, preferably the deposit device being a pin or pin-likestructure constructed and arranged, under computer control, to dip intoa cleaning station periodically and in operation, dip into a selectedvolume of fluid carried by the mobile fluid storage device, preferablythe mobile fluid storage device being a multiwell plate having 96 wellsor multiples of 96 wells, or a spacing of 9 mm or a submultiple of 9 mmand preferably the apparatus including a driven stage for moving thefluid storage device into registry with the deposit device undercomputer control for enabling dipping of the deposit device into apreselected fluid volume; in another case preferably the mobile storagedevice is an annular ring that retains a supply of fluid by surfacetension.

The invention also features the method of use of all the describedapparatus in depositing fluid drops, especially the fluids mentioned inthe specification, and in subsequent cleaning.

In the various methods, preferably the receiving surface is fragile, orsoft, preferably the receiving surface is porous or microporous orfibrous, preferably comprising nitrocellulose, nylon cellulose acetateor polyvinylidine fluoride or a gel, preferably the member defining thesoft or fragile receiving surface being mounted on a rigid carriermember, either directly or upon an intermediate soft or resilient buffermember.

Preferably the method is employed to deposit a fluid selected from thegroup of biological fluids described in the specification, preferablythe material being a biological probe or a chemical for reaction withbiological material, a fluorescing material, an ink, dye, stain ormarker, a photoactive material, or a varnish or an encapsulant or anetchant, or a cleaning or neutralizing agent.

Another broad aspect of the invention is the method of depositing abiological fluid with a pin or pin-like structure comprising supportingfluid within a ring by surface tension, and moving the pin or pin-likestructure through the ring in the manner that a relatively small drop ofthe fluid is held at the end of the pin by surface tension and depositedon a receiving surface, and moving the ring to a cleaning station priorto resupply.

BRIEF DESCRIPTION OF THE DRAWINGS

In the Figures:

FIG. 1 depicts a spotting system employing the deposit action depictedin FIG. 1A, combined with a cleaning station and a central supply offluid specimen.

FIG. 1A depicts a mobile sub-reservoir that travels from one depositposition to another with a separate deposit device illustrated as adeposit pin.

FIG. 2 depicts a spotting system employing the deposit action depictedin FIGS. 2 and 3, combined with a cleaning station and a central supplyor fluid specimen.

FIG. 2A is a side view and FIG. 2B a top view of a deposit head,comprising a deposit pin and an annular sub-reservoir through which thedeposit pin operates, while FIGS. 3A-3D depict a sequence of stages ofthe deposit action of the head of FIG. 2A.

FIG. 4 is a perspective view of an assembled deposit pin constructedaccording to FIG. 4A combined with a respective supply ring.

FIG. 4A is a diagrammatic side view of a combination of a deposit pinand a cooperating support that provides lateral constraint of the pin.

FIG. 5 illustrates an arrayer system, employing a group of assemblies ofFIG. 4 constructed for commercial use.

FIG. 6 is a perspective view of a machine for depositing dots ofbiological fluid in dense array upon a series of microscope slides.

FIG. 6A shows features of the control system software and method forconducting the deposit and cleaning action.

FIG. 7 depicts a station for removing liquid, washing and drying the pinand ring at one location.

FIG. 8 is a perspective, partially cut-away view of a preferred cleaningmodule while FIG. 8A is a magnified view of a portion of FIG. 8.

FIG. 9 is a view of a preferred relationship of a pin and associatedmobile reservoir ring while FIG. 9A illustrates certain dimensions otherembodiments of FIG. 9.

FIG. 10 and 10A are side and bottom constructional views of the moduleof FIGS. 8 and 8A.

A. PREFERRED EMBODIMENTS

In preferred embodiments a deposit pin D of small cross-section isemployed with a mobile fluid reservoir to which the pin is repeatedlyexposed, the pin being sized and shaped to define and retain on its tipa drop of fluid from the reservoir, the drop containing only enoughmaterial to deposit a single dot.

Presently we prefer that the rim of the tip of the pin be “square”, i.e.that, in profile, the end surface of the tip of the pin be substantiallyat a right angle to the side surface of the pin, and that the pin sidesurfaces be smooth. Preferably the pin is round in transversecross-section, though it may be of other shapes. It is found that arraysof fluid dots between about 20 microns to 375 microns can be depositedusing biologic fluids of conventional concentrations, by employingdeposit pins that have, in their tip regions, a wire or wire-likegeometry of diameter (true diameter or cross-section dimension) betweenabout 0.001 inch (25 microns) and 0.015 inch (375 microns). The smallertips, i.e. tips smaller than 0.012 inch (300 microns) are referred tohere as “microtips”. A preferred range of tip sizes is between 50microns and 250 microns.

Tightly packed arrays of deposited dots of fluid can be achieved, i.e.arrays with center-to-center spacing between dots of less than threetimes the dot diameter, often only twice or one and one half times thedot diameter.

Provision of a suitable mounting and drive of the deposit pin enables alow and predictable contact force upon the receiving substrate (a “softlanding”) despite variations in the height of the substrate, e.g. due tovariations in thickness of microscope slides or slide-like members uponwhich the fluid dots are applied. Superior results can be obtained bycontrolling the deposit pin force upon the substrate to less than theorder of one gram, or 0.5 gram, preferably about 0.3 gram.

The systems enable spotting of, e.g., a full set of 40 microscope slideswith 10,000 spots per slide, a process that may require a few hours to afew weeks, depending upon the number of pins operating simultaneously inone head. The instrument may operate unattended for many hours at atime.

In preferred mechanical systems, the pin is compliantly mounted andresponds to resistance force transmitted to the pin by the fluid ormechanical contact with the substrate, so that the tip of the pin stopsdespite overtravel of the driver.

B. MOBILE FLUID RESERVOIRS AND INTERACTION WITH DEPOSIT PINS ANDCLEANING STATION

For making a succession of deposits of the same fluid, as when preparinga number of microscope slides or membranes or providing redundantdeposits on a single substrate, a mobile sub-reservoir, periodicallyre-supplied from a stationary central supply, travels with a depositdevice to be near the deposit locations.

As illustrated in FIG. 1A, a deposit head comprises the deposit pin Pand the sub-reservoir SR which is sized to contain sufficient sample toenable deposit of a number of dots before being resupplied.

After deposit of drop F at target S, e.g. on a microscope plate R or aplate carrying a delicate or soft membrane, the assembly proceeds toplate R₁, pin P is resupplied with drop F₁ by being dipped into andraised from the accompanying sub-reservoir SR, the new drop is thendeposited at target point S₁ at plate R₁, and so on.

The system is especially useful for preparing a number of microscopeslides or membranes. The central fluid supply CS advantageously is amultiple well plate as conventionally used in microbiology, such as a 96well plate. Cleaning and drying station CL is also provided. The depositsequence includes moving the assembly of deposit device and mobilesub-reservoir under computer control through cleaning and drying stationCL, thence to central supply CS at which the sub reservoir SR issupplied with a selected fluid sample, e.g. from a selected well of a 96well plate. Then the group moves over a series of receiving surfacesR-R_(n), for deposit of fluid dots at selected locations on each, alsounder computer control. This sequence is repeated a number of times,with controlled selection of different fluid samples (from, e.g.,different wells of the central supply CS) for respectively differentlocations on the plates R or other receiving surfaces. Data thatcorrelates locations with respective specimens is recorded in memory andused in subsequent scanning or reading.

The technique of using a deposit tool that accurately sizes eachindividual drop, such as the deposit pin with square rim profile at itsmicrotip, combined with a mobile local sub-reservoir that accompaniesthe tool and carries a volume sufficient to supply a sequence ofdeposits, has a number of important advantages. The technique, based onsmall motions, saves time in avoiding repeated travel to a centralsupply; it avoids evaporation losses of long travel, so that the dropcreated can be very small and the deposited array very dense; and thedots can be kept consistent in size and concentration or biologicalcontent across the array of dots being deposited. The time overheadinvolved in cleaning, transporting and picking up the specimen is keptsmall so that, overall, deposits can be made very fast, inexpensivelyand of desired small size.

In this way a large number (for instance ten to one hundred) identicalmicroscope slides or membranes can readily be prepared by repeatedmotions over an array of the slides or membranes. Each substrate cancarry dots of many different fluids based upon resupply of thesub-reservoir from different wells of a number of multiple well platesintroduced to the system, and cleaning between changes of fluid.

The sub-reservoir and the deposition device are decoupled, in beingmovable relatively to one another for resupply and for deposit, as wellas being coupled or at least coordinated, to move laterally over thereceiving surface to produce the series of deposits. The sub-reservoircan move into a resupply position, e.g. by immersion into a well, orunder a suitable pipette. It can be made to hold sufficient fluid inexcess of that required for the sequence of deposits, or to expose asufficiently limited evaporative area, that concentration of thesubstance of interest in the fluid is not substantially affected byevaporation during the multiple deposit sequence.

Thus we have described deposit devices constructed to precisely define asingle fluid drop of desired size, obtained from a mobile sub-reservoir,deposit the drop at a precisely positioned, discrete location and returnby local movement to the sub-reservoir for another drop. In thepreferred embodiment of FIGS. 1 and 1A an axially reciprocable depositpin is employed for this purpose in conjunction with an accompanyingsub-reservoir in which the pin is directly dipped. Alternatively, aprobe that dips into a local sub-reservoir as by coordinated rotationalor translational motions of a wire or pin, can accomplish this action,as can other designs.

Referring now to FIGS. 2A and 3A-D, another preferred mobilesub-reservoir is an annular reservoir ring 14 which, as depicted, holdsfluid between its interior opposed surfaces by surface tension effects.

Deposit pin 12, having a sharp rim 12F at its tip, of diameter dselected to produce the desired size of the deposited dot, is mounted inaxi-symmetric relation to sub-reservoir ring 14. Ring 14 has an internaldiameter d₁ significantly larger than the pin diameter such that fluidspace fs exists between the pin and the inner surfaces of the ring. Theouter diameter d₂ of ring 14 is sized smaller than the well of a centralsupply plate, so that the ring can be immersed in it for supply.

During the deposit sequence of FIGS. 3A-3D the ring 14 is heldstationary by its support rod 15 while the deposit pin 12 is moved by anassociated driver D through a sequence of vertical positions. In thestart position, the end 12D of pin 12 is drawn above the lower surfaceof the retained fluid R_(f) held by surface tension effects between theinternal surfaces of ring 14. This is shown in FIG. 3A. (The pin, forillustration, is shown withdrawn fully above the retained fluid R_(f),although that is not necessary.)

Comparing FIG. 3A with FIG. 2A, by downward movement of the pin tip fromabove the lower surface of the retained fluid R_(f) (FIG. 3A), to belowthat surface (FIG. 3), the tip of the pin, with its sharply defined rim,picks up from the retained fluid R_(f) a precisely sized volume of fluidas drop F. The drop is then deposited in the sequence shown in FIGS. 3Cand 3D. Interestingly, as the pin penetrates the miniscus, surfacetension pulls the fluid laterally from the pin with the result that amuch smaller amount of fluid can remain on the end of the pin than inthe case in which a pin is dipped and then raised from an open supply.In many cases this volume-limiting action is highly desirable, as itpermits monolayers or at least very thin spots to be deposited, savingmaterial and providing a uniform fluorescing mass that enables moveaccurate reading to occur.

At the resupply position, see FIG. 2, the annular ring 14 is moveddownwardly by its support rod 15 for immersion in the well of the supplyplate while the pin 12 remains stationary at a higher elevation, or itmay assist in the resupply action, by being present within this ringwith its end, for instance, flush with the bottom of the ring, as shownin FIG. 2.

At cleaning and drying stations the lower surfaces of the pin 12 andring 14′ are vertically at the same level.

At a washing station the ring and pin may both be subjected toreciprocation in the same or opposite vertical directions to assist thecleaning process.

The multipurpose cleaning station illustrated in FIG. 7 is sized toreceive deposit pin 12 and supply ring 14. It has an annular nozzle 200directed inwardly against the pin and ring to subject the parts to aconical flow from fluid sources such as compressed air, pressurizedliquid and aerosols. The flow is directed past the parts 12, 14 to atrap having disposable filter 202 that intercepts material being removedfrom the parts. The trap may be associated with a vacuum pump. As shown,nozzle 200 is associated with a secondary air path 204 to enable nozzleflow to induce a flow of secondary air when desired.

The system of FIG. 7 is useful to remove sample liquid from the parts,to effect cleaning, and to dry the parts. For example the pin and ringare first exposed to one or more simultaneous or successive fluidcurrents or blasts of continuous or pulsed flow that blow remainingsample fluid from the parts and into the trap. Subsequently, a fluidstream of liquid or air may expose the parts to cleaning fluids such asliquid streams or aerosols containing water-borne detergent. This isfollowed by rinsing with pure water from the nozzle. Following washing,an air current from the nozzle, supplemented by induced air flow 204,can dry both pin and ring, in which case the air streams may be heated.

There is an advantageous relationship of pin and ring for resupply ofthe ring. When the ring is immersed in selected well W of a multiwellplate, FIG. 2, the pin is present within the confines of the ring, tohelp the ring pick up the fluid. Their surface tension propertieseffectively cooperate to compete with the surface tension effects of thewalls of the well that resist removal of small quantities of the fluid.In the presently preferred relationship, the bottom tip surface of thepin is substantially aligned with the lower surface of the ring.Withdrawal of the assembly from immersion in well W withdraws a desiredamount of fluid, pendent as a large meniscal drop, bounded by the pickup ring. This quantity, protected and supported by the ring, is thenavailable for deposit in tiny drops by repeated projection of the pinthrough the ring.

The sub-reservoir ring may have various advantageous forms such asaxially adjacent circular rings, multi-turn helical shapes, closedcylinders, open rectangular rings, open “U” shaped structures, etc. Thusthe term “ring” or “annular ring” as used generally refers to any closedor partially closed structure that, through surface tension effectsbetween adjacent or opposed surfaces, supports a volume of liquid in aspace through which a deposit device such as deposit pin 12 can operate.The size of the opening or bore of the ring, as well as the size, forinstance, of wire or ribbon that forms the cross-sectional shape of thering is selected in relation to the properties of the fluid (e.g.viscosity and surface tension), the number of deposits to be made from agiven fluid charge in the reservoir ring, and the size of the depositpin that is to move through the ring.

The size and shape of the deposit pins that cooperate with these andother sub-reservoirs also vary depending upon the application. It ispossible to employ pins of various transverse cross-section, e.g. squareor hexagonal or even rectangular or oval cross-section of equivalentarea to round cross-section pins. Especially for small dots, the pinsmay advantageously have stepped transverse cross-sections, e.g. may havean extremely small cross-section at the deposit end, to size thedeposited drop, stepped to a larger cross-section in the main body, forproviding structural stability.

For implementing the broad concept of a local, mobile supply, othertechniques than those shown can be employed. An example is a large diprod, an enlarged version of a deposit pin, from which a large dropdepends, which travels with the pin and is visited by the pin by asuitable motion, such as rotation. Such respective dip rods and otherdevices may be provided cleaning stations similar to that shown.

C. OPERATING SYSTEM

Some advantageous, novel operating systems that implement the foregoingprinciples will now be described.

DIP & DOT SYSTEM

The mobile reservoir shown in FIG. 1 can be a multi-well plate. Undercomputer control, an appropriate X,Y stage brings the chosen fluidresupply well in alignment under the pin. The pin is then controlled todescend, make contact with (dip into) the reservoir fluid and rise,taking a small amount of fluid in the form of a pendant drop.

The pin is raised sufficiently to permit the pin and reservoir toseparate e.g. by computer controlled sideways movement of the reservoir,freeing the pin to descend unobstructed to deposit its small fluid dropon the targeted location on the substrate.

With appropriate transport motions of pin and multi-well supply, theprocess is repeatable at each location where a sample of the selectedfluid is desired, the fluid in the proper well being repeatedly broughtinto alignment with the proper pin for resupply and deposit in thedesired location by computer control. Each time a pin is commanded toreceive a fluid from a well different from that of its previous command,the pin is moved by computer control to liquid removal, cleaning anddrying station CL, to prevent contamination.

For efficient operation, a multiplicity of pins may be used at spacingsthat match the pattern of wells, enabling each pin to reach inside aseparate well of the multiple well reservoir such as a 96 well plate ora 384 well plate, as are known in the field of biochemistry andanalytics.

The pin assembly and its driving mechanisms are preferably mounted on aprecision XY gantry as they require good positional accuracy. Themultiple well plate may be provided with two degrees of freedom in aplane parallel to the deposition plane and can be indexed under the pinassembly on a separate structure. Because of the relatively large sizeof the wells, the translation assembly for the plate may have lowerpositional accuracy than that of the pin. In some cases the multi-pinassembly and the mobile multi-well reservoir share the same X,Y gantryto advantage.

Under computer control, the multi-well reservoir separates in the Ydirection from the pin assembly and the Z stage is actuated to cause thepins to form deposits upon substrate R. Then, the multi-well reservoirmoves under the raised pins into appropriate alignment, employing bothY₂ and X₂ motions under computer control. By Z motion the pins P_(A) dipinto the commanded wells for resupply. The pins rise again, themulti-well reservoir moves laterally with Y₂ motion out of the way andthe deposit process is repeated at new targeted X,Y location of the pinson substrate R or R₁. While this mobile reservoir technique is usefulwith pins of any construction, the advantage of high accuracy of thelinear motor indexing system is enjoyed when the pins are constrained inspace to a highly accurate repeatable position relative to theircarrier, with the high density pin arrangements made possible by thestructures shown. Advantage is also taken of the positional accuracy inrespect of cleaning. The pins are moved to station CL, FIG. 1, and enterrespective holes using the ganged actuator or individual actuators thatdrive the pins in supply and deposit action.

MULTIPLE PIN PATTERNS

In the preferred embodiments, two rows of 4 or more pins P, preferablyconstructed according to FIG. 4A are spaced apart in a 9 mm square gridpattern matching the spacing of the wells of a 96 well plate. Thispermits transport of fluid from all 96 wells, 8 wells at a time to anassembled array of microscope slides, and directs the composition of 8spaced apart blocks of approximate dimension each 8×8 mm on each slide,covering in total approximately 18×36 mm sq. Each pin deposits in arespective one of the 8 blocks simultaneously with a single actuation ofthe Z drive. The head repeats the action on each of the set of slideswith the same fluid, and is then cleaned to be ready for fluid fromdifferent wells. The same pin may be used to deposit the same fluid at anumber of directed positions in a given block, and/or upon thecorresponding block of a number of slides each having the set of 8spaced apart blocks, the deposits on the slides being much closer thanthe spacing between wells. By following an appropriate sequence, allwells may be visited by respective pins. Actually the dot size inpractice is much smaller than illustrated and dot density much greater,e.g., with as many as 50,000 or 100,000 dots carried by a singlemicroscope slide.)

In a similar preferred embodiment, a grid of 12 pins has 2 rows of 6pins each, again spaced apart in a 9 mm square grid pattern to match thespacing of the wells of a 96 well plate. This arrangement permits thetransport of fluid from all 96 wells, 12 wells at a time, and directsthe composition of 12 spaced apart blocks of approximate total area18×54 mm sq.

With either arrangement, or in the case of many more pins, the method isperformed under computer control to form a more densely packed array offluid dots than that occurring in the multi-well plates, e.g. arrays of20 micron to 375 micron diameter dots with similar spacing between dots,using all fluids in the plate.

Just as the pins are located on 9 mm centers, the square arraysthemselves are distributed on 9 mm centers over the face of thesubstrate. By following an appropriate pickup sequence by repeatedsamplings, all wells are visited, the pins being conveyed under computercontrol to the cleaning station between change of fluids. The contentsof the multi-well plate or a number of plates are thus distributed fromthe low density distribution of wells in multi-well plates to highdensity arrays.

Similarly, again using 9 mm pin spacing, with two rows of 6 pins each, asequence of samplings from the wells under computer control collectssamples from all wells and uniquely distributes them as high densityarray deposits in 12 squares on the microscope slides or othersubstrate.

The benefit of such groups of pins is to create a large number ofdeposited dots simultaneously on one or many microscope slides orsubstrates. This can substantially reduce the time and cost required tocreate high density arrays.

The assemblage of pins on a 9 mm square grid can also be used totransport fluid from plates with well spacing constructed on a squaregrid that is based on sub multiples of 9 mm, such as plates with 384wells or 864 wells or 1536 wells, etc. The high accuracy of the computercontrolled gantry system enables accurate placement of the selectedwells with respect to the pins, and the pins with respect to thereceiving substrate and the cleaning station.

It is evident that using the same logic, pins can be assembled in denserconstructions to fit plates with smaller well spacings.

The denser the array, the tighter the location tolerances for thelocation of each small dot. The systems of laterally constrained depositpins of e.g. FIG. 4A, or as shown in the parent U.S. patent applicationscited above, which are hereby incorporated by reference, areparticularly capable of repetitive production of precise high densityarrays. In the embodiment of 4A, the mounting tube, at its lower end, isshown to have been spun, to form a generally conical bottom ledge which,in interacting with a downwardly facing conical surface of the pin,tends to center the pin. Using these principles, the mode of supplyingthe tips with fluid can be selected in reference to the nature of thefluid as well as other operating parameters. A ring supply mode will nowbe described.

PIN & RING SYSTEM

The pin assemblies as shown in FIG. 4A and in FIGS. 1-4 of the parentPCT application can be used with a simple axial ring translationmechanism. As the fluid needs to be picked up from a rather large well,a sufficiently compact arrangement of multiple pins and supply rings ispossible. FIG. 4 shows the relationship of a pin and ring without theirsupport or actuation mechanisms. Seen in FIG. 4 are supply ring 14, pintip 12 d, ring body 35 from which a support rod segment 15 extends tothe ring 14, pin shaft 12 b, the pin seat 13 formed on pin body 12 a andpin guide 12 g. FIG. 5 shows a set of eight such pin and ringassemblies. It is evident that any number can be assembled in thisfashion. In FIG. 5 one can see the pin holding structure, and the ringholding structure and their respective linear stepper motors Z₁, and Z₂that enable relative vertical motion. The Z₁ motion for deposit on areceiving surface preferably involves overtravel, the compliance of thedeposit pins relative to the receiving surface, as provided by spring 22in FIG. 4A, ensuring proper deposition over a range of surface heights.The respective supporting linear guide rails for X and Y motion providea complete array-forming mechanism. FIG. 5 illustrates a commercialrealization of the design which attaches to the Y stage linear motor ofa deposit system.

Deposit pin 12 can also be mounted on a parallelogram, cantileverconstruction as described in the parent applications which are herebyincorporated by reference.

FIG. 2 suggests a deposit cluster 28 of independently operated depositpins, formed by a number of the deposit assemblies described in theFIGS. 2A, 2, 4 and 4A. These employ a number of independent drives D,one to drive each pin and one to drive each ring in Z direction forpicking up and depositing fluid, and sensors to indicate to the controlelectronics the position of the operative elements.

The cluster may step to a selected X or selected X,Y position, at whicha number of different motions under computer control may be caused tooccur, picking up and depositing fluid in any order at any locationdesired, and visiting the cleaning station as required. Such a clusterconstitutes a particularly versatile tool when employed withconventional microtitre plates.

In such embodiments the aliquot carrier rings 14 and pins 12 are spacedin the cluster at 9 mm center-to-center distances or multiples thereofto facilitate operation with 96 well plates (in which the wells arespaced at 9 mm on center intervals, with 8 rows of 12 holes). Higherdensity plates also employ this configuration and have the samefootprint but employ more holes, 16×24, with hole-to-hole resistance of9/2 mm, to provide “384 plates”. The system described can be employedwith 96 and 384 well plates, as well as any arbitrary arrangement.

The versatility of the cluster of independently operable deposit pins isillustrated by the following examples.

An array of sub-reservoir rings, e.g. set at 9 mm center-to-spacing, maybe indexed in X,Y direction along with their pins and the rings may bedriven down (or dropped) simultaneously into respective cleaningcavities or for supply or resupply from four wells of a conventional 96or 384 well plate, in an action similar to the systems previouslydescribed.

After suitable indexing, the set of pins may be driven downsimultaneously to form deposits at a corresponding number of places, inthe same format as the supply plate.

Alternatively, during resupply, one sub-reservoir ring may be dropped topick up material from a selected well while all others remain in theirpassive positions. Then the cluster may be moved until the next ringarrives at the same well or another selected well, at which point it isdropped to pick up its aliquot, and so on, so that all of the rings mayhave the same fluid from the same wells or different fluid from anyselected wells.

The cluster 28 may be moved in X,Y direction between pickup or depositactions of successive pins so that, e.g. all of the pins deposit thesame or different fluid on a single slide at selectable addresses oreach pin addresses a different slide, but at a different location, ortwo pins address one slide and two another slide, or the deposits aremade one on top of another, etc.

The operator may also choose not to have one or more of the devicesoperating.

Thus it is seen that dense clustering of independently operable depositpins and rings can enable high speed, versatile operation.

Actuation of all aliquot carriers simultaneously by one actuator and allpins actuated by another single actuator, to provide a multiple pinhead, realized with flexure-mounted pins is also possible. For example,using linear stage techniques, two rows of four pins at 9 mm spacing inboth X and Y directions are all mounted on a frame which is reciprocatedalong a rail via a carriage by a single motor. This causes the eightpins to move simultaneously. Likewise, two rows of four cooperatingrings 14 are mounted on a common ring support 124, with the samespacing. The single support is driven via carriage by one motor.

Referring to cleaning stations CL in FIGS. 1, 2 and 6, 6A and 7 and thedetailed views, FIGS. 8-10, a preferred cleaning and drying station fora set of pin and ring assemblies for plain pins or other tools used inthe environment, employs a corresponding set of venturi passages inwhich respective pin and ring assemblies, pins or tools are introduced.This provides “one-stop” shopping for a set of cleaning conditions suchas alcohol denaturing, cold water rinse, detergent wash, hot waterrinse, hot air dry. A supply plenum is fed with pressurized fluid ofselected quality from an air compressor 90, nitrogen tank, etc. In oneexample compressed air is employed for all cases, into which areselectively introduced by controls suggested by valves 92, agents tocreate the respective aerosols of water, soapy or detergent solution,alcohol, etc., followed by heated air for drying, as produced by theresistance heater in the air flow path.

CLEANING

High density microarrays require spotting tools with correspondinglysmall features. The smaller the features, the more difficult it is toclean and prevent contamination.

The downwardly directed set of venturi passages of FIGS. 8 and 8A, towhich the tools gain access by entering from the top of the chamber, isa very effective means of cleaning in many ways. First, it produces highpressure cleaning; second it enables the selection of the temperature ofthe fluid or air without moving the pins or rings; and it can be veryefficient. In certain cases, the high velocity air may drag oraccelerate washing fluid or may entrain abrasive elements, for instancebeads of polyethylene or other material with the simple use of fluidunder pressure to provide the energy for the cleaning.

From the point of view of infectious or dangerous material, the benefitfrom this new mode of cleaning is that the contaminant will not escapeinto the working zone, such as the enclosed spotting area of the arrayerin FIG. 6. The enclosure ensures that the instrument is situated in acontrolled environment. The flows of the venturi tubes are arranged tohave an educator or pump effect, drawing (i.e. entraining) air from theworking zone and preventing contaminating back flow from the cleaningchamber.

This type of cleaning is especially useful for the arrayer, but moregenerally has broader potential as a cleaning station for smallinstruments, in particular where escape of contaminants is to beavoided, for instance in a hospital or food preparation setting. The jetis aimed down from the access portals at the to of the module, throughwhich the devices to be cleaned enter. Because of the contained natureof the jet action one may employ very high fluid pressure, hightemperature and strong cleaning agents while the immediate environmentis protected from contamination or disturbance. Thus adaptations of theprinciple provide a nearly universal cleaning tool for biological andother laboratories. The air jets enable reaching surfaces to whichaccess is difficult. The fluid agent or the cleaning agents arecontained in all directions and do not escape. They do their work ofcleaning while being contained and are retrieved and disposed of withlittle chance of escape.

The system comprises basically a containment chamber with entry portalssized for introducing of a work object, especially a pin and ringdeposit assembly. The oriented jets directed away from the accessportal, convey fluid against the devices to be cleaned, that candissolve coatings or contamination. The entry manifold enables injectionof fluids for dissolving, washing and drying which can be sequencedwithout moving the parts being cleaned. The system easily interfaceswith a logic system or computer to achieve automated cleaning action.The system is particularly well suited for microbiology and generesearch deposit assemblies which are arranged in high density toproduce microarrays.

ARRAYER

The gantry of an arrayer, now to be described, can carry one deposithead, a cluster of independently operable single pin heads, or amultiple pin head of the various designs described above. Combinationsof these are also possible.

FIG. 6 is a perspective view of a slide preparation machine forpreparing microscope slides or other substrates such as delicate soft orporous membranes carried on rigid supports. Its function is to rapidlydeposit a high density array of fluid dots of different compositions ona number of identical substrates, employing the microdot technology ofthe present invention. As shown in FIG. 6, there are a number of 96 wellsupply plates 31, serving as the central fluid source for resupply ofmobile fluid storage devices, and a cleaning station CL.

Horizontal base plate 200 provides a support structure to hold theoperating components. Fastened to base plate 200 are vertical sub plates210, 220, 230 and 240. Fastened to these plates is a dual axis motionsystem 250, comprising X and Y axis devices 260, 270 for providing X andY motions, in a parallel plane.

The guide rails of the X and Y axis devices, 260, 270 are parallel tobase plate 200, to carry deposit cluster 28 in X,Y motions in a planeparallel to base plate 200.

The X axis device 260 is a commercial device available from Adept ofJapan. It moves at a high rate of speed in a controlled manner using arotary servo motor with a drive screw and a shaft position encoder,employing digital and analog technology. Carried by X-axis device 260 isan orthogonally arrayed Y-axis device 270 which is a smaller versionthat operates in the same manner as the X-axis device.

The deposit cluster 28 comprises eight deposition mechanisms, gangedtogether on a mounting structure. These devices may be in accordancewith the various structures shown.

After a deposition sequence is complete, the X and Y terminal drives thecluster of depositing elements to the cleaning station CL. In someembodiments they may be passed over the wells from which the fluidoriginated or other receptacle and subjected to air blast as by theventuri passage of the cleaning block described, to dislodge excessfluid, or excess fluid may be removed by abrupt stopping of rapiddownward movement to dislodge excess fluid.

The fluid removal station according to FIG. 7 is employed is essentiallyan earlier version of the arrangement of FIG. 8, where air flow removesremaining fluid from the pins and rings. The array of pins thus purgedof remaining fluid by air blast is then, by warmed air, washed andrinsed by liquid or aerosol streams and dried, while remainingstationary.

As an alternative to the top access multiple venturi scrub chamber inthe system of FIG. 6, the array of pins and rings of a cluster 28 may beheld over a vessel of water for cleaning, in which the water level ismaintained and a pump constantly replenishes the water. Blotting paperor a cellulose sponge may be provided against which the pin and ring areblotted for fluid removal or drying. By considering the relativeclumsiness of such techniques, one gains a better understanding of thesignificance of the venturi chambers described.

The control system of the arrayer of FIG. 6 has controls for the X and Yaxis movement and also home center for the X and Y axis. The actualposition of the carriage that the lead screw is driving is sensed so thecarriage can be driven home and then the counter is initialized soprecision motions can be made along both the X and Y axes. As previouslydescribed, each deposition head may have two motors, a pin drive motorand a ring motor, that are commanded from the control computer.

For deposit on microscope slides including slide-like rigid memberscarrying delicate, soft membranes, the slides are fastened to the table,or placed in register with guides in a known position. Features on thebase plate of the machine locate the slides in predeterminedorientation.

For use in high volume production contexts, the system described in theforegoing figures preferably employs a rapidly moving, laterallyconstrained, axially compliant pin as shown in FIGS. 4 and 4A, in adeposit cycle of less than 0.1 second, in which impact and vibration isminimized, with the natural frequency of the system more than 10 Hz, inmany cases preferably 20 Hz, a pin contact pressure of less than 1.0gram, preferably less than 0.5 gram in many cases preferably about 0.3gram, and the system employing damping.

Each pin as shown in FIG. 4A is mounted in its own mounting tube bythreading into a header plate, and can be readily individually removedand replaced for service or for providing pins or different sizesappropriate to different protocols.

Pin pressure on the substrate is light, and fluid splatter or separationconditions are thus avoided, despite the high speed of action, so thatdots of fluid of uniform shape are consistently formed at preciselycontrolled positions, even on soft or fragile receiving surfaces, thusproviding more accurate arrays, and as well, keeping the nearbyenvironment clean and free of tapping or impacting elements.

In the deposit action of the deposit pin, by raising the pin aftercontact of the drop on the substrate, the combined effects of inertia ofthe stationary fluid and surface tension (and of gravity, whendepositing downwardly, which is normally preferred) act upon the drop offluid to overcome the force of surface tension exerted by the liftingpin. The fluid drop preferentially stays with the surface of thesubstrate, and the pin, substantially devoid of fluid, is free to bereplenished and move rapidly to its next destination.

As the volume of the fluid is accurately specified by use of standardsizes of pin, and standard conditions, and the position of the pin isprecisely constrained as by the mounting tube of FIG. 4A, spots, dotsand microdots of consistent size and precise location are produced, thatenable an improved degree of quantification of observed results. Inparticular, this is of importance in support of the new field ofquantified fluorescence microscopy.

D. EXAMPLES OF NOVEL METHODS OF USE

The systems described are useful with any native fragment of DNA, orpre-synthesized oligonucleotide of any length. There being norestriction as to chemicals, any non-photoreactive chemical as well asphotoreactive chemicals can be employed. Likewise dyes that are usefulto detect presence or absence of DNA may be selectively deposited inregistry with previously deposited spots or microdots of biologicalmaterial, and vice versa. Indeed, in one example, the accuracy of thespotting technique employed here, is capable of spotting standardfluorescing sample dots which can be employed as a calibration standardfor the instrument to support quantified fluorescence microscopy.

Among the many biological materials that may be spotted at high speedare fragments of nucleic acids, e.g. DNA, RNA or hybrids such as PNA(peptide nucleic acid), PCR (polymerase chain reaction) products, clonedDNA, and isolated genomic RNA or DNA, as well as synthetic analogs.

Also included are restriction enzyme fragments, full or partial lengthcDNA, mRNA or similar variations thereof, proteins such as proteinreceptors, enzymes, antibodies, peptides and protein digests;carbohydrates; pharmaceuticals; microbes including bacteria, virus,yeast, fungi, and PPLO; cells and tissue fragments; lipids,lipoproteins, and the like; plastic resin polymers, small particulatesolids in suspension, etc.

The deposition system may also be employed to deposit catalysts,reagents and encapsulents upon previously deposited material of any ofthe types above or, as mentioned below, to create an array of sites ormicro-wells for later reaction or growth of such material, or to assistin neutralizing or cleaning the deposit or reaction sites, as in thecase of highly toxic or virulent substances. The high effectiveness andcontainment provided by the cleaning system enables working withvirulent or dangerous materials that can enable safer diagnostics anddisease control, and can extend the range of useful reactions that maybe investigated.

The most basic use of the arrayer is to create high density arrays ofnucleic acid on a porous or solid, flat surface, generally a microscopeslide or slide-like support. Deposit is possible on fragile or softsurfaces such as microporous membranes or gels, glass cover slips,plastic surfaces, and wells of a microplate, or any substrate, which maybe previously coated or derivatized, and serve as a recipient surface.

In particular, membranes and gels are desirable to enable high densityanalysis with automatic equipment, using materials familiar to thefield, on which much of the important, historical data has previouslybeen acquired. Also, deposit on fragile glass cover slips is desirableas they are thinner than microscope slides, easier to maneuver, and whena beam of light is transmitted through them for transmission microscopy,better light capture occurs because the slip is thinner and less lightabsorptive. The system has the capability of spotting on plasticsurfaces without scarring or deforming the surface.

In addition to applicability in bioresearch and clinical diagnosis, thedeposition and instrument cleaning system has applicability in thechemical laboratory, e.g. to analyze fluids, such as for water quality,or to experiment with resins, for instance polymerization reactions, toconduct experiments in small quantities of many different varieties,e.g. to determine optimum ratios and optimum selection from a host ofslightly varying examples. The range of usefulness is broad withapplication to the new, popular paradigm of a large number orsimultaneous experiments based on small quantity samples, differenttemporal sequences, different kinetics of reaction, and differentmixtures. In all of these cases, the deposit and cleaning system is aprecise way of manipulating small amounts of liquid, solids in liquidsuspension and cells in suspension, under controlled and safeconditions.

Deposition with the systems described leads to rapid and preciseobservations, reduction in the number of trials for a given experimentand improvement in the statistical significance of the data. Costsavings and improved experimental procedures can be realized.Quantification of results at accuracies heretofore unknown may beattained by consistent and precise dot formation that enables improvedsignal-to-noise ratio in detection, when sensing the difference between,e.g., the fluorescence of a deposited spot and the immediately adjacentbackground surface of the substrate.

The system is useful in many environments due to the attributes of thedeposit and cleaning apparatus, and the techniques by which movement andcontrol is effected.

In another method employing the deposit and cleaning system, an etchantfluid is provided in a local reservoir ring. The pin of the deposit pindistributes the etchant in tiny, precise spots or microdots in a desiredarray across a reactive substrate surface. For instance, for formingmicro-wells for containing fluid, the device deposits an acid such ashydrochloric acid in an array of small dots upon a silicon substrate. Anetching reaction occurs, and the substrate is then neutralized andwashed, to produce a corresponding array of small wells, after which thetools of the arrayer may be washed of etchant without risk ofcontamination or harm to the adjacent activities.

Arrayers as described can also be used for color printing of fabrics,paper etc., where the 96 well plate holds different color inks or dyes.The area to be printed is the entire reach of the gantry less the colorsource and washing station.

The arrayer can be used to generate a single printed circuit board,e.g., prototype boards, or boards for limited volume production, wherethe machine is employed to deposit varnish or photoresist or otherprotective coating material to define the regions of the copper clad orother substance which need to be preserved from acid etching. Likewisethe arrayer may be employed to deposit photoactive substance forproduction of “biological” deposits using lithographic techniques, allwith the assurance that the deposit elements will be cleaned to avoidcross-contamination.

A variation of the spotter mechanism employs, in a fashion analogous tothat of a modern milling machine, a set of interchangeable heads havingdifferent capabilities. Under computer control, an X-Y carriage of thesystem is moved to select a desired head which is carried across thesubstrate to be cleaned and perform its function. In some instances thedevice selected may be a sub-reservoir ring from a set of such ringsthat have different internal diameters or are formed of different wireor ribbon sizes, or are of different sizes to enter different wells,etc. These provide a variety of carrying capacities for fluids ofdifferent viscosities or for use with deposit pins of different sizes.Likewise, different sizes of deposit pins can be selected from a set ofpins to vary the size of the spot to be deposited. Heads can also beselected that provide other devices for preparing for or conductingexperiments or for the production of reference or diagnostic well platesand slides.

In some cases the selection and use of devices can be conducted undercomplete computer control to enable automatic performance of amulti-task experiment un-attended by the technician, in which the toolsor devices are subjected to automated cleaning, e.g., with the system ofFIG. 8, during the regular course to avoid contaminated experiments.

In addition to depositing spots of fluid upon a standard microscopeslide, and upon porous or soft membranes and other delicate substrates,it is possible and advantageous to deposit spots on substrates ofsignificantly larger area and on other substances and on surfaces havingspecial formations, for instance upon substrates having micro-cavitiesthat have been formed by the instrument itself, by one of the techniquesdescribed above. Plates delivered with the micro-cavities preformed inthe substrate may also be used, and aligned for deposit of fluid byautomatic controls of the instrument, or the control system of the unitis advantageously provided with a vision system that “reads” thelocation and pattern of the array of micro-wells, and adjusts itselfautomatically or under operator control to accurately deposit dots offluid in wells. Likewise a vision system can be employed to identifydifferent types of cleaning chambers that have been installed, e.g. bybar code identification to ensure that each device to be cleaned entersa suitable chamber into which it fits and which has appropriate featuresfor cleaning imaging special features of the tool or other device.

F. CONCLUSION

In the various ways described, a large array of fluid deposit sites maybe established and managed in a precise, repeatable manner that employsthe same concentrations or reactions or precisely varied concentrationsand reactions, under conditions that prevent contamination and enablehigh speed or automatic action. This may be done to enable examination,to promote reaction or growth processes in biotechnology, life sciences,chemistry, pollution detection, process control and in industry ingeneral.

Thus, beyond an instrument for low-cost preparation of microscope slidesand membranes for biotechnology research, there has been contributed auniversal and widely variable set of systems, instruments, methods andproducts that can advance research and industry.

Numerous other embodiments not described in detail here can apply theprinciples described to particular applications and are within the scopeof the claims.

What is claimed is:
 1. A cleaning station for a deposit device locatedin the vicinity of a work zone for the device, the cleaning stationcomprising a confinement chamber having a portal sized to receive thedeposit device, and a flow nozzle arranged adjacent the portal toproduce a cleaning or drying flow directed generally inwardly of thechamber along said device such that said flow is induced by a jet fromsaid work zone creating at least a partial suction into the chamber. 2.The cleaning station of claim 1, wherein the cleaning station is adaptedto enable one or more fluids to flow through the flow nozzle.
 3. Thecleaning station of claims 1 or 2, wherein the cleaning station isconstructed to produce a flow of compressed air through the flow nozzleand a control for introducing one or more fluids to the flow.
 4. Thecleaning station of claim 2 in which said one or more fluids includealcohol, rinse water and a cleaning solution.
 5. The cleaning station ofclaim 1 in which the deposit device or the like has multiple separateworking parts, and the station defines a plurality of said portals andnozzles that are arranged to admit said separate working parts.
 6. Thecleaning station of claim 1 in which the deposit device comprises adeposit pin and a reservoir ring through which the pin operates, thenozzle arranged to direct flow between the pin and the reservoir ring.7. A cleaning station for a deposit device comprising a set of separatepin or pin-like structures constructed respectively to form individualspots on a substrate, the set of said separate pin or pin-likestructures supported on a common member, and a cleaning station defininga confinement chamber having a set of top portals corresponding to therelative location of said set of said pin or pin-like structures,actuator mechanisms for lowering the respective pin or pin-likestructure through the respective portals and a flow assembly constructedto direct a cleaning flow inwardly in the vicinity of the portals, alongsaid pin or pin-like structures.
 8. A cleaning station for a depositdevice for depositing an array of spots on a receiving surface, saiddeposit device including a drop-carrying surface, and a fluid sourcecooperatively arranged to deposit said spots on said receiving surface,said cleaning station comprising a cleaning device constructed andarranged to clean said drop-carrying surface by employing a flow ofcleaning fluid delivered by a venturi fluid jet constructed and arrangedto blow said cleaning fluid at said drop-carrying surface.
 9. Theapparatus of claim 8 wherein said jet is constructed and arranged toblow said cleaning fluid at least partially along a length of saiddeposit device toward said drop-carrying surface.
 10. The apparatus ofclaim 9 wherein said drop-carrying surface is located at least partiallywithin a confinement chamber.
 11. The apparatus of claim 10 wherein saiddeposit device has a pin-like structure with said drop-carrying surfacedisposed in a distal end of said pin-like structure.
 12. The apparatusof claim 8 wherein said drop-carrying surface is located at leastpartially within a confinement chamber.
 13. The apparatus of claim 8wherein said deposit device has a pin-like structure with saiddrop-carrying surface disposed in a distal end of said pin-likestructure.
 14. The apparatus of claim 8 wherein said drop-carryingsurface has a diameter less than 375 micron.